Appearance

King Thwomp appeared to be a normal Thwomp that Kamek enlarged.

Battle

King Thwomp behaves similar to a regular Thwomp, but moves from side to side in addition to dropping when Mario is underneath, which will break a layer of the blocks that make up the floor. When all layers have a hole through them, Mario and company must aggro him to force him to crash through the floor, and fall into the bottomless pit below.

Trivia

The fight with King Thwomp is similar to the final battle against Bowser in Super Mario Bros. 3, as players must force the boss to fall into a bottomless pit sealed by layers of blocks.

The Winged Thwomp in Super Mario Maker behaves similarly to this boss, moving from side to side when not dropping or rising.